1. The problem statement, all variables and given/known data The 2-kg collar C is free to slide along the smooth shaft AB. Determine the acceleration of collar C if (a) the shaft is fixed from moving. (b) Collar A, which is fixed to shaft AB, moves downward at constant velocity along the vertical rod, and (c) collar A is subjected to a downward acceleration of 2 m/s^2. In all cases, the collar moves in the plane. My question is about the case c. 2. Relevant equations ∑F=m*a T3. The attempt at a solution The answer model also says that a(along shaft) does not change, so why doesn't this method work?